It's not enough Crysis had some DX10 workarounds lurking inside its demo code. No, they had to go and leave (or place, for your convenience? Who knows) more neat stuff in there. Stuff like weapons, vehicles and bad guys from the full version, which you can easily get hold of with a bit of a code cut 'n' paste. Once cut 'n' pasted (instructions at link below), the next time you fire up the demo you'll find every gun in the game just sitting there, waiting for you, along with some tanks and an attack chopper. Which should guarantee you a few more good times between now and November 16.
Crysis Crisis Deepens [Rock, Paper, Shotgun]